Rocket signal device



Sept 3, 1963 R. o. STEFAN ETAL 3,102,477

ROCKET SIGNAL DEVICE lllll Filed Nov. 21, 1961 HIIIIIHI HIIIIHIH 55H0555 0. 57E/:nu

/vro/v G LAI/vc; 64 64 INVENTORS.

BY 35 5g /rroe/VEY.

United States Patent Gli ice anni?? Patented Sept. 3, 1963 3,102,477RCKET SIGNAL DEVECE Russell 0. Stefan, Downey, and Anton G. Lang, Los

This invention relates to pyrotechnic signal producing `devices andrepresents anfimprovement over the device entitled Flare Gun which isdisclosed in our copending application for U.S. Letters Patent SerialNo. 72,901, filed December 1, 196i), now Pat. No. 3,044,360. The devicedisclosed in said `application comprised a tubular launcher embodying aspring impelled striker, the diameter of said launcher `approximatingthat of a fountain pen, and a cheap, single-use cartridge of slightlylarger diameter which screws into the launcher and provides, in onepackage: a tiring barrel; a projectile containing a signal charge and areadily ignitable fuse charge; and a percussion cap detonatable byimpact of the launcher striker therewith to both ignite said fuse chargeand propel said projectile to a height of approximately 100 yards.

It is an object of the present invention to provide such a signa-ldevice in which the fuse charge is ignited in a manner to delay itsburning and thus assure that a substantial portion of the mass of thefuse will remain unconsumed during a :considerable portion of the`upward flight of the projectile, thereby contributing to the momentumaiding in the ascent of the projectile and also deferring the ignitionof the signal charge until the projectile has reached an altitude whereit will lbe an effective signal.

Another object of the invention is toA provide such a device in whichthe burning of the fuse charge, thus prolonged, applies a sustainedrocket thrust axially to the projectile in the direction the device ispointed when fired,

thereby increasing the altitude attained hy the projectile.

A further object of the invention is to provide such a cartridge, theshell of which is injection cast of plastic material thereby greatlylowering the cost of such cartridges. i d

Prior attempts to employ cast plastic as the material for cartridgeshells have encountered the tendency for percussion caps mounted in suchshells misiiring morefrequently than is allowable.

Still another object of the present invention is the provision of aplastic cartridge shell for a pyrotechnic signalv device or the like inwhich misring of the percussion .cap is practically eliminated. r

It is also an object of the present invention to provide a novelsignal-charge-containing projectile, adapted for use in such acartridge, and a novel method of making said projectile whichcontributes substantially to the attainment of the foregoing objects.

The manner of accomplishing the `foregoing objects as lwell -as furtherobjects and advantages lwill be made manifest in the followingdescription taken in connection with the accompanying drawings in whichFIG. l is an elevational View, drawn approximately to full scale, of lapreferred embodiment of the invention held erect with the ring pincocked ready for firing.

FIG. 2 is an enlarged, fragmentary, sectional view of the inventiontaken on line 2--2 of FIG. 1, and shows the firing pin of the inventionin safety position.

FIG. 3 is a View similar to FIG. 2 illustrating the firing of saidcartridge with the projectile only partly extended rocket `fuse chargein the projectile is ignited only in a centralized area of preciselylimited size las the projectile is propelled from the cartridge.

FIG. 4 is a view similar to FIG. 3 and illustrates the projectile infull iiight upwardly under the impulse of the momentum of its dischargefrom the cartridge, -aided by the rocket thrust produced by the Iburningof the rocket fuse charge of the projectile. p

FIG. 5 is an enlarged sectional yView to a scale of approximately twiceactual size, of the cartridge of the invention with the elements thereofseparated axially so that they .may be individually illustrated as theyappear prior to assembly in the cartridge.

FlG. 6 is a diagrammatic illustration of the steps involved in themethod of manufacture o fthe flare projectile of the invention.

Referring specifically to the drawings, the present invention isillustrated therein as embodied in a pyrotechnic signal producing devicelil 'which includes a launcher 11 and a cartridge 12.

The launcher l1 comprises la cylindrical tube -13 which is about 1/2inch in outside diameter and is internally threaded at its .oppositeends. Formed longitudinally in the tube i3 is a tiring slot 1lihaving asafety notch 15 `formed laterally therefrom near its upper end and acooking notch 16 formed in the opposite direction laterally Vfrom saidfiring slot at the opposite end of the latter.

Screwed into the internal threads in the upper end of the tube 13 andsecured against rotation by a punched indentation 17 in the tube is atiring pin stop 1S, this having an axial here 1lb with a deep conicaldownward counterbore 2u.

Closely fitting and freely slidable within the tube 13 is ya cylindricalring pin 25, the upper end of which is tapered to t iiush within the[conical counterbore Ztl and terminates in a tapered striker 26 which isof a smaller `diameter than the bore t9 so las to pass readilytherethrough. The tiring pin 25 is provided with a radial hole 27, justibelow the tapered upper end thereof, and a cocking pin 2d having acylindrical knurled head 29 is driven into the hole 27 so as to "oepermanently assembled with the tiring pin 25 and restrict movement ofthe latter in the tube 13 to the limits deiined by the tiring slot `14and notches l5 and 16.

A coiled expansion spring 30 ts slida-bly into the lower end of the tubei3 and is held compressed against the lower end of the firing pin 2:5 bya screw plug 3l. which screws into the threads in the lower end of thetube i3.

The cartridge l2 of the device 10 constitutes the ammunition which isused with the launcher 11 in each tiring `of the device lil, and eachcartridge provides its own tiring barrel so that it is unnecessary forthe launcher to be provided with such a barrel.

Referring to FIG. 5 which illustrates the component parts of `acartridge l2 separated axially in the order in which they are assembledto `form the cartridge, the three principal components of the cartridgeare seen to -be a shell 32, a projectile 33 and a percussion cap 34.

The shell 32 may be die-cast of aluminum or of the alloy known as diecast metal ibut, to lower the cost of y the cartridge 1.2 this shell ispreferably injection molded of a plastic of high tensile strength. Theonly plastics which have proved satisfactory i-n making the shell 32 todate are polycarbonate resin which is known in the triade as Lexan, andacetal resin which is known in the trade as Delfin The shell 32 includesa cylindrical tiring; barrel 35 which preferably has 'an inside diameterof approximately .575 inch and a wall thickness of at least .05 inch.The upper end of the barrel 35 is Iopen and the lower end is anexternally threaded nipple 41. The base 40 closes the lower end of thebarrel 35 and has a deeply concave conical inner surface 42 which formsa `gas expansion pocket at the lower end of the cylindrical tiringchamber 43 provided by the barrel 35. The juncture of the conicalsurface 42 with the chamber 43 forms an annular shoulder 44.

Formed axially in the nipple v411 is a bore 45 having a counterbore 46the latter forming an annular shoulder 47 at its juncture with saidbore. The counterbore 46 is designed to tightly receive a metalreinforcing sleeve 4S which is provided with an inturned flange 49 atits inner end which is thus ibrought to rest against the annularshoulder 47 of the shell 32. The internal diameter of the sleeve 48 issuch as to tightly receive the percussion cup 34 and the latter ispressed into said sleeve. The function of the sleeve 48 is to provide arelatively rigid base for supporting :the cap 34 so as to insure`detonation of the latter when the device is fired. In the absence ofsuch a reinforcement the plastic material of which the shell 32 is madewas found inadequate to prevent frequent misfiring of the caps mountedtherein, a circumstance which would be intolerable in the signalingdevice to which this invention relates. Providing shell 32 with thereinforcing sleeve 48, however, has practically eliminated failures fromthis source.

The percussion cap 34 is preferably a center fire primer capotsubstantial power and the cap of this type identified as the No. 250Magnum `Rifle and Pistol Cap put out by Cascade Cartridge Co., Lewiston,idaho, has proved entirely satis-factory. v

yMany difficulties were encountered in the development of projectile 33to the point where this satisfactorily performs its intended function inthe invention. The preferred method in the present invention ofproducing the projectile 33 is -diagramrnatically illustrated in FIG. 6.The principal element of the projectile 33 is a very thinwallled metalcup which is preferably made of aluminum but which can also be made ofother relatively combustible metals such as zinc, magnesium or diecasting metal. The Wall of cup 55 is preferably about .005 inch inthickness. The method of utilizing this cup .in the f manufacture ofprojectiles 33 includes the use of la steel platform 56 which isprovided with a multiple of cylindrical recesses 57, each |being of 4asize to just snugly receive one of the cups 55. Each of the recesses 57is provided with a cup ejection hole 58. The six steps of the method ofthe invention for making the projectiles 33 are illustrated in adjacentrecesses 57 of the platfrom 56. In actual practice the platform 56 isprovided in multiples and where a step involves a pressing operation adifferent press is equipped with a'bank of plungers, one for each of therecesses 57, and that step is performed on all these recesses in asingle :operation :of that press.

The process starts with supplying each of the recesses 57 of one of theplatforms 56 with a cup 55 and the filling ofall the cups in theplatform with a are signal cornposition -which constitutes the signalcharge of the projectile. Where it is desired that the projectile 33give a bright red light as a signal, this composition is made up ofAapproximately 70% of powdered magnesium (200 mesh), 25% orf potassiumperchlorate, 4% of strontium oxalate (for red color), and about 1% .ofIgum arabic tor moistening the mixture. Where the gum arabic needsthinning a trace of dextrine or `linseed oil is added. When this mixturehas the form of a relatively dry paste it is forced into the cups v55 tolill the same, as shown in recess ainFlG. 6. j l

The next step of the process, illustrated in recess b, consists inplacing the platform 56 in a press which is provided with a bank ofplungers 59, one for each .of the recesses 57 and lowering theseplungers to press the composition occupying the cups 55 to greatlycompact this in these cups and form this composition into .a signal I 14 charge 60. The lower end spherical in shape and has a rounded tit 61formed axially thereon so as to impress this shape onto the exposedsurrace of each of the signal charges 60 when this step has beencompleted. In order to get the desired compactness of the material ofthe composition thus pressed into the cup 55 to Iform a signal charge60, a pressure is applied lon this mixture by each of the plungers 59 offrom 1500 to 4000 pounds in the step just described".

The next step of the process of niakingithe projectile upward travel ofthe projectile when lthe device 11 is fired.

The next step of the process of making projectiles 33 is to set theplate 56 aside for approximately twelve hours to Vlet the signal charges60 formed in the shell 55V to thoroughly idry out.

A composition .is now prepared for forming a rocketfuse charge 64 themouth of the projectile 33. This composition preferably comprises 75% ofmeal-prime(% j of which is blasting powder and 1/3 charcoal) and 25% ofthe composition used in forming signal charge 60. This is made into adry paste and packed into the hollow space in the mouth of each off thecups 55 and then pressed tightly therein by placing the platform '56 ina press equipped with a bank of rams 65 las illustrated in connectionwith recess e in FIG. 6.

The platform 56 loaded with projectiles 33 on which all of the foregoingsteps have been performed so' as to complete these projectiles is nowset aside to permit thorough `drying orf the rocket-fuse charges 64,after which thel projectiles 33 are ejected from their recesses 57 by aIbank of ejector rods '(not shown) extending through the holes 58.

The projectile 33 has an outside diameter which permits it to veryloosely fit into the tiring chamber 43 of the shell 32 when assembling acartridge 12. When this assembly takes place the projectile 33 ispreceded into the chamber by a cardboard disk 70 having a small holeabout 1,46 of an inch in diameter. When the disk 70 comes to rest on`the shoulder 44 therefore it supports the projectile 33 with the uppersurface ofthe disk close to the adjacent surface of the nocketJfusecharge 64 with the central hole 71 of the disk exposing only a smallaxial portion of that surface of the charge 64, as shown in FIG. 2. Tocomplete the assembly of the cartridge 12, a second cardboard disk 72 ofthe same dialneterras the disk 70, but imperforate, is inserted in themouth of tiring chamber 43 so to rest against the upturned bottom of theprojectile 33, the 'latter being inverted before insertion into theshell 32, Both of the disks 70 and 72 have an outside diameter whichsnugly fits the firing chamber 43. The nal step in assembly of thecartridge 12 comprises painting the upwardly exposed tface of the disk72and the exposed mouth portion of the barrel 35 above said disk with athin coating of varnish-like sealing material 73 which will not fusewith the plastic material `of the shell 32 but adheres theretosuiiciently to exclude moisture from the cartridge 12.

The threaded nipple 41 of the cartridge 12 has threads of the same pitch`as the internal threads in the upper end of the tube 13 and is thusadapted to be screwed into the upper end of said tube to make a tightthreaded t with the latten with the end lof the nipple very close to orin contact with the outer end of the striker stop 18 (FIG. 2). When thecartridge 12 is thus mounted on the launcher 11 the axially mountedpercussion cap 34 of the cartridge is aligned with and close to theupper end of each plunger 59 is semi-A r1 o j of the hole 19 in thefiring pin stop 13. Users of the signal device 11 are instructed toalways have the firing pin 25 on safety position, that is with thecocking pin 28 in theV notch 15 as shown inFIG. 2 before screwing acartridge 12 into launcher 11 as above described and as shown in FIGS. 1Iand 2, and preferably never to do this excepting immediately before andpreparatory to the tiring of a signal withr the device 10. Theseprecautions are of course to prevent the accidental discharge of thedevice resulting. in injury to person or property.

Operation The cartridge V12 having lbeen screwed snugly into thelauncher 11 as shown in FIG. 2, with the firing pin 25 on safety, thenext stepin the operation of the device vis to cock the tiring pin asshown in FIG. 1. This is done by holding the device in theleft hand,pointing the cartridge 12 away -from the face and preferably upwardly,and then with the thumb yof the right hand pulling the cocking pin 28downwardly out of the notch 15 into the tiring slot 14 and to the lowerend of said slot and then rotating the tiring pin 25 to swing the pin 28into the .cooking notch 16 where said pin is held fast by the upwardpressure of the spring St) against the striker 25 and the fact that thecooking notch l16 slants slightly up- A wardly from the longitudinalaxis of the tiring slot 14.

The device `10 is now held aloft vertically by gripping the lowerportion of the launcher 11 in the right hand, with the right thumb to:the right of the knurled cocking pin head 29, and the device is yfiredby using this thumb to shift the cooking pin 23 out of the clockingnotch 16 and into the firing slot 14. This releases the tiring pin 25from restraint, coiled spring 30 thereupon rapidly impelling the tiringpin upwardly to the full limit allowed by the firing slot 14 whichterminateswith striker 26 penetrating the percussion cap 34 of thecartridge 12.

This detonates the cap 34 which `contains a suciently heavy charge ofpercussion powder to fill the pressure pocket 42 in the bottom ofthefiring chamber 43 with combustion gases under a pressure ofapproximately 2400 pounds per square inch. Flame produced in thisexplosion passes through the hole 71 in cardboard disk 7i) and ignitesthe'rocket-fuse powder charge in the pro` jectile 33 ,in an `area of thedownwardly exposed surface of this charge approximately the same size asthe hole 71. f The precise limitation in the size and location of thisarea in which the charge 64 is ignited has a signicant bearing on theoperation of the device lit as will be subsequently explained in detail.

Bearing upwardly against the inturned flange 63 of the projectile 33 andoutwardly .against the tiring charnber 43 of the barrel 35, the disk 7dacts as a packer -against the `escape ofthe gases produced by thepercussion cap 34 whenrthis is detonated, except by the propulsion t ofthe projectile 33 from the lbarrel 35. Although adequate for sealingpurposes, the bond between the l sealing film 73 and the cartridgebarrel 33 is readily broken by the gas pressure tending to expel theprojectileV 33 from the-cartridge.' FIG. 3 shows the tiring of thedevice with the projectile only partly out of the cartridge while FIG. 4shows the projectile in free tiight upwardly l and indicates how thisflight is aided by the rocket action of the restricted symmetricalburning of the rocket-fuse charge 64. The latter view also indicates therelative instability of the card-'board disks V'7d and 72 so that theturbulence of the combustion gases propelling the pro jectile from thecartridge (andthat of the surrounding atmosphere) deects these disks toone side or the other of the axial path of the projectile so as not tointerfere `with the ight of the latter along this path.

The-limitationby thel disk 7i) of the area in which the rocket-fusecharge 64 is ignited has two principal results of great benefit in theoperation of the device 10.

The regulated and symmetrical burning of the charge G4 during thisperiod causes it to impart a substantial rocket thrust upwardly againstthe projectile 33` throughout the initial one-third of its upward ightwhich considerably offsets the air resistance impeding such travel sothat the projectile reaches a` much higher `altitude than wouldotherwise be the case without this assistance.` Retardation in theconsumption of the -two charges in the projectile 33 also slows up theloss of weight in the projectile and thus renders the momentum of theunconsumed portions of the charges more effective in ofsetting the airresistance to Vthe upward travel of the projectile. Finally, the delayin igniting the signal charge 60' due to the feature being discussed,renders the light produced by the burning of this charge much moreeffective because the projectile 33 is at a substantially higheraltitude while this charge is burning.

The inturned flange 63 of the projectile 33 serves an important functionin reinforcing the mouth of the cup 5S so as to resist splitting of theedge of the cup which this shell otherwise has a tendency to do, whenfired, and which results in fragmentation and loss of burning particlesof the charges in the projectile which are visible in the air anddetract from the strength of the signal given. The inturned tiange 63also narrows the mouth of the projectile thereby retaining chargesdtland 64 in the cup 55 at least up to the time in the Hight of theprojectile when the flange 63 is consumed by the iiame produced by thenal burning out of the charge 64 and the coincidental ignition of thesignal charge `6i?. From this point on (which starts about midway in theupward flight of the projectile 33) the material of the cup 5S burns atthe exposed edge of this along with the material of the signal charge6). At the conclusion of the burning of the charge 6th-the entire cup 55has been consumed and there is nothing left, even in the form of an ash,to fall to earth. This mode of operation of the projectile 33 is ofgreat importance in eliminating iire hazards in the use of the inventionand the very thin combustible sheet metal of which the cup 5S is formedaccelerates the rate of combustion of the cup and gives assurance thatthe cup is completely consumed in the air. y

While the composition above described of the material used in making thesignal charge 60l in the projectile 33 is for the purpose of producing ared Hare signal, other colors can be produced in such a Hare bysubstituting other color producing chemicals for the strontium oxalatecomponent of said composition. `For instancerbar` ium chlorate when sosubstituted would producea are with a green color. It is also to beunderstood that the signal charge 60 may be composed of chemicalsadapted to produce a dense cloud of smoke in order to manufacture acartridge 12 adapted for giving a smoke sigout departing from the spiritof the invention or the scope of the appended claims.

The claims are: 1. A protechnic signal producing cartridge comprising:A. a shell including:

(l) a cylindrical thin-walled barrel enclosing a ring chamber;

(a) said barrel being of adequate strength to withstand, withoutexternal support, the firing of said cartridge,

(2) a base closing one end of ysaid barrel (a) to form` the breach ofsaid chamber and present to said chamber a concave surface forming a gasexpansion pocket at the inner end of said chamber (b) said baseproviding an axial threaded nipple having an axial bore thereincommunicating with said pocket,

(c) said bore having a counterbore in its outer end portion to provide acap receptacle;

B. a percussion cap mountedinl said receptacle;

C. a fwadding disk slidably fitting within said chamber against theperipheral portion of said base,

(1) there being a small hole formed axially in said disk;

D. a signal projectile slidably tting within said chamber against saiddisk, said projectile including:

(l) -a thin-walled cylindrical cup, inverted in said chamber to presentits mouth to said disk,

1(2) a signal powder charge pressed into said cup to partially till thesame, l

(3) and a 'fuse Ypowder charge pressed into the mouth of said cup oversaid signal charge and approximately completing the filling of said cupwith said charges; and

E. sealing means applied to the open end of said barrel andto saidprojectile to retain the latter in said V`barrel to exclude moistureyfrom said barrel.

2. A combination as` in claim 1 in which said sealing means comprises acardboard disk'slidably fitting within the open mouth of said chamberagainst said projectile; and a coating of plastic sealing materialapplied to the exposed faceof said disk and the internal surface of saidbarrel exposed above said disk. *3. A protechnic signal producingcartridge as recited in claim 1 wherein the concave surface presented bysaid shell base to said firing-chamber is frusto-conical with analtitude approximately equal to the radius of said iiring chamber.

4. A pyrotechnic signal producing cartridge as recited in claim lwherein (a) the shell thereofis jet-molded of a high tensile strengthplastic, v

(b) the counterbore in the shell nipple is substantially larger indiameter and depth than said percussion cap, and

w(c) a metal reinforcing sleeve having an inturned annular flange at itsinner end is provided, said sleeve being pressed into said counterbore,the latter receiving said` sleeve with a pressed fit, .to produce areceptacle for Isaid percussion cap, said cap being mounted with a pressit in said sleeve, to rest against said flange.

5. A pyrotechnic signal producing cartridge as recited in claim lwherein said flare projectile cup is comprised of a relativelycombustible metal selected from the group consisting yof aluminum,magnesium, zinc, and die-casting metal.

6. A pyrotechnic signal producing `cartridge as recited in claim 5 inwhich the are projectile cup is provided at its mouth with an inturnedange to strengthen the mouth portion of said cup during the tiring ofsaid projectile and to confine the powder charges within said cup duringthe initial portion ofthe flight of said projectile.

7. A pyrotechnic rocket are projectile which will -be totally lconsumedwhen tired upwardly into the air, thereby practically eliminatingincendiary hazards incidental to its use, said projectile comprising:

A. a thin-walled cylindrical cup with a thickness of approximately .005inch, said cup being made of relatively highly combustible metal,

B. a flare powder charge pressed under high pressure into said cup topartially llfthe latter and leave a deep, concave depression in saidcharge;

C. a fuse powder charge pressed into said cup to over- Y lie said arepowder charge and ll the depression formed therein; and v D. -a curledannular inturnedv lip on said cup for engaging said fuse charge andretaining said charge in :said cup, said lip `and cup lbeing consumedupon the burning of said charges.

erf

8. A pyrotechnic signal producing lng:

A. a shell including:

( 1) a cylindrical' thin-walled barrel enclosing a chamber, 2 a

(a) said barrel being of adequatestrength to withstand, without externalsupport, the

cartridge` comprisiring of said cartridge, (2) a base closing `one endof said barrel,

(a) to form the breech of said chamber and present to said chamber a`concave surface forming a gas expansion pocket at the inner end of saidchamber,

(b) said base providing an axial threaded Vnipple having anYaxial-.boi'etherein cornrnunicating with said pocket,

(c) said ,bore having a counterbore in its outer end portion `to providea cap receptacle; i

B. a percussion cap mounted in said receptacle; C. a signal projectileslidably fitting within said chamber, said projectile including: v

(l) a thin-walled cylindrical cup madeV of a relatively highercombustible metal,

(2) a are powder charge pressedunder high pressure into said cup .topartially iill the latter, (3) and a fuse powder charge pressed into4the mouth of said cup over said ilare powder charge and approximatelycompleting the iilling of said cup; .and D. sealing means applied to theopen end of said barrel and to said projectile to retain the latter insaid barrel to exclude moisture from said barrel.

9. A pyrotechnic rocket flare projectile which will be totally consumedwhen red upwardly into the air, thereby practically eliminatingincendiary hazards incidental to its use, said projectile' comprising:

A. a thin-walled cylindrical cup made of a relatively highly combustiblemetal,

B. a flare powder charge comprising:

(a) magnesium powder of approximately 200 mesh, 70% by weight, (b)potassium perchlorate, 20% by weight, (c) a color producing additive, 4%by weight, selected from the group consisting of strontium oxalate andbarium chlorate, and (d) gum arabic, 1% by weight; andv C. a fuse powdercharge pressed into said cup to overlie said are powder charge andllzthe depression formed therein, said fuse powder charge compris- (a)magnesium powder of approximately 200 mesh, 2 5 -by weight, (b) blastingpowder, 50% by Weight,l (c) powdered charcoal, 24% by weight, and (d)gum arabic, 1% by weight.

References Cited in the iile of thispa'tent UNITED STATES PATENTSyDriggs et al. Feb. 20,

OTHER REFERENCES Military Explosives, TM 9-1910, Dept. of Army TechnicalManual. April 1955, pages 284-288.. (Copy vin Div. 46 and Library.)

1. A PROTECHNIC SIGNAL PRODUCING CARTRIDGE COMPRISING: A. A SHELLINCLUDING: (1) A CYLINDRICAL THIN-WALLED BARREL ENCLOSING A FIRINGCHAMBER; (A) SAID BARREL BEING OF ADEQUATE STRENGTH TO WITHSTAND,WITHOUT EXTERNAL SUPPORT, THE FIRING OF SAID CARTRIDGE, (2) A BASECLOSING ONE END OF SAID BARREL (A) TO FORM THE BREACH OF SAID CHAMBERAND PRESENT TO SAID CHAMBER A CONCAVE SURFACE FORMING A GAS EXPANSIONPOCKET AT THE INNER END OF SAID CHAMBER (B) SAID BASE PROVIDING AN AXIALTHREADED NIPPLE HAVING AN AXIAL BORE THEREIN COMMUNICATING WITH SAIDPOCKET, (C) SAID BORE HAVING A COUNTERBORE IN ITS OUTER END PORTION TOPROVIDE A CAP RECEPTACLE; B. A PERCUSSION CAP MOUNTED IN SAIDRECEPTACLE; C. A WADDING DISK SLIDABLY FITTING WITHIN SAID CHAMBERAGAINST THE PERIPHERAL PORTION OF SAID BASE, (1) THERE BEING A SMALLHOLE FORMED AXIALLY IN SAID DISK; D. A SIGNAL PROJECTILE SLIDABLYFITTING WITHIN SAID CHAMBER AGAINST SAID DISK, SAID PROJECTILEINCLUDING: (1) A THIN-WALLED CYLINDRICAL CUP, INVERTED IN SAID CHAMBERTO PRESENT ITS MOUTH TO SAID DISK, (2) A SIGNAL POWDER CHARGE PRESSEDINTO SAID CUP TO PARTIALLY FILL THE SAME, (3) AND A FUSE POWDER CHARGEPRESSED INTO THE MOUTH OF SAID CUP OVER SAID SIGNAL CHARGE ANDAPPROXIMATELY COMPLETING THE FILLING OF SAID CUP WITH SAID CHARGES; ANDE. SEALING MEANS APPLIED TO THE OPEN END OF SAID BARREL AND TO SAIDPROJECTILE TO RETAIN THE LATTER IN SAID BARREL TO EXCLUDE MOISTURE FROMSAID BARREL.